• 천문학회지
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• 제30권1호
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• pp.71-81
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• 1997

We have studied the IR properties of molecular clouds in the region of the supershell GS234-02 using IRAS and COBE data. The mean values of dust color temperature and optical depth at $240{\mu}m$ are derived to be $15.4\pm1.5K\; and\;9.0\pm5.7\times10^{-4}$, respectively, which agree well with those determined by Sodroski et al.(1994) for the outer Galaxy. Mean IRAS colors, $R_{12}/100= 0.074,\; R_{25}/100= 0.052,\; R_{60/100}= 0.219$, indicate that the abundance of PAHs is enhanced but other particles are nearly the same as those of the solar neighborhood. We found the anticorrelation between $R_{100/140}\;and\;R_{140/240}$. It cannot be explained by the thermal emission of traditional big grains. The anticorrelation implies that, at high ISRF, $T_{100/140}$ underestimates the equilibrium temperature, while $T_{140/240}$ overestimates it and, at low ISRF, vice versa. Therefore we propose to use the intensity ratio, $R_{100/240}$ as a dust thermometer.